Hot gas engine of the bellows type



Sept. 23, 1952 J. w. L. KOHLER ETAL HOT GAS ENGINE OF THE BELLOWS TYPE Filed Oct. 26, 1949 m/ven/rqgs .mcaa w/z LEM LAURA-W5 AOl-ILEA CORNELIUS arro Joli/x52:

W/LLEM HE'A/DR/K 57/675 AUGUST ALBERT L/EEE AGENT.

Patented Sept. 23, i952 HOTJGASENGI-NE' on museums-TYPE.

This invention relates to hot-gas engines comprising two spaces, the volumesrot 'which are varied with 'a phase-d-i-ffrence and in which a thermodynamic I cycle is performed during the operation of. the engine.- The:- term" -.hot-gas engine's -is 1 to be understood toinclude' refriger ators an'di heat pumps operating: according to the reversedhot gas en'gineprinciple.

Hot-gas engines are, as a rule, constructed as reciprocating engines. The use of p-istons usually involves-the following difficulties. The working medium-leaks away, incertain; cases to a considerable extent, from thespace-on one side of the piston tothe space on the other side of the piston. Thisleakag'eoiworking medium involves a' material thermal loss. A; further difficulty is that it is, as a rule, necessary to lubricate the pistons. This .lubricationrequires continuous supervision, sincetliere is" a risk that somelubricating oil may findits way into :the regenerator, which considerably lessens the efficiencysoi. the regenerator i A third difilculty is that the. friction forces acting :on the ipiston may attain a fairly high value. The aforesaid difficulties have a detrimental eifect upon the power output of the engine. In certain cases it is possible to mitigate one of the said difficulties, but this, as a rule, results in the other difiiculties being increased.

Furthermore, in the embodiments of hot-gas engines hitherto known, in which compression and expansion take place for the greater part in the working spaces of variable volumes and heating or cooling in a separate heater and cooler, the expansion and compression will, as a rule, not be isothermal but approximately adiabatic. This results in the working process being no longer reversible. Thus, for example, in a hotgas reciprocating engine, the mean temperature of the medium is lower than it should be at the end of the expansion. In flowing through the heater, the medium ultimately assumes the temperature required. On compression, the temperature becomes, on the contrary, higher than it should be, so that the temperature must decrease during the passage of the medium through the cooler.

The object of the invention is to provide an improved hot-gas engine. According to the invention, a hot-gas engine comprising two spaces, the volumes of which are varied wtih a phase difference and in which a thermodynamic cycle is performed during operation of th engine, is characterized in that the wall of at least one of the spaces of variable volume is shaped in the -Albert Liebe;*Eindhoven,' Netherlands, assign- I I i i (Sm te-Hartford:National Banl-i'and Trust Coml J 1.. .pany;?Hartford;; ConnJ-as trustee V W plicationfic'tober '26, 1949,} SerialNoI 12366171 jln'theNetherlands December 20,1948

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form of b'el-l'owsfli-the driving-gear of the engine and the bellows -beingmechanieallyconnected such--that --movement of the driving. 'gean is ate tendedwithanin'creaseor a: decrease in the volume of this space; the exchange of thermal; energy being' -eifected through -th'e wall of the v bellows. This ensures an'approxi-matelyisothers mal-expansion eorcompressio'n in these working spaces, -so that an appreciable improvementrin. power output ensues. struction may dispense with? the external heater' and/orcoolen I gas iengine comprising bellows .maygbexrealised. iifitwo lset si of :"b'ell'ows are'larranged .:in;.line with each other;theradjacentlterminal walls: fizthesev spaces being secured Ion either :sideiof; azpartitiom having heat-insulating propertiesi'l Since it. is,tas afruleydimcultdor the rod mechanismqwith: th'efisaoftwhich: the' bellowsam varied inlvoluma'gto .bextaken through "these bele lowsgittiscpreferable to varyzthewolumeseof the: spaces:bounded byi'theiibellows;witlrxthe use ofxa driving rod mechanism which engages-with the partition and which is connected to" the driving gear of the engine externally of the bellows.

In one embodiment of the inventiomia hot-gas engine in which at least three cycles are perbellows remote from each other beingconnected by way of a common rod system QtothedriVing, gear and the adjacent terminal walls-having arranged between them a channelsystem which permits each space, bounded by a set of bellows, of each system to communicate with a space of another system. This embodiment allows of very short connection ducts between the spaces.

The aforesaid embodiments of the invention may be used with particular advantage for refrigerators.

In order that the invention may be more clearly understood and readily carried into effect, it will now be described more fully with reference to the accompanying diagrammatic drawing, given by way of example, which shows one form of construction of a hot-gas engine according to the invention.

The figure shows a twin-cylinder hot-gas engine comprising bellows, the exchange of thermal energy between the working medium of the engine and the external means for the supply and dissipation of thermal energy being efiected through the wall of the bellows.

The bellows of this engine, 1. e. the heated In this case this con;

bellows 30 and the cooled bellows 3|, are connected by connecting rods 36 and 31 respectively, to a drive shaft 38. The bellows indicated in this engine have a double function. Firstly, they serve to vary the volume of the working spaces and secondly they serve as a wall through which thermal energy is supplied to or withdrawn from the working medium taking part in the thermodynamic cycle. This afiords the advantage that the working medium traversing the cycle is expanded and compressed substantially isothermally. The engine shown in this figure is intended for use as a refrigerator operating according to the reversed hot-gas engine principle. Space 32 about the bellows 30 serves as the reirigerator space, so that thermal energy is supplied from the space 32 through the wall of the bellows 30 to the working medium. Thermal energy is withdrawn through the wall of the bellows 3| from the working medium to space 33 about the bellows 3|, with theme of a cooling medium, which flows into this space at A and leaves this space at B. The two working spaces. 1. e. the working space in the bellows 30 and that in the bellows 3| communicate with each other through a duct 34 comprising a regenerator 35. Since the thermal energy is supplied and withdrawn through the walls of the bellows, the heater and the cooler may, in this case, be dispensed with.

It will be obvious that embodiments of the invention other than that described above fall within the scope of the invention and that many known constructions and arrangements adapted to be used in hot-gas reciprocating engines may be used or may be modified for use in a hot-gas engine according to the invention.

What we claim is:

1. A hot gas engine comprising means forming a cold working space of variable volume and adapted to receive a working gas, means forming a hot working space of variable volume and connected to said cold working space, one of said 4 means including a bellows-like member, means for heating the working gas within said hot space, means for cooling the gas within said cold space and means to vary the volume of the hot working space, and coldsworkingspace in phase differences. v

2. A hot gas engine comprising means forming a cold working space of variable volume and adapted to receive a working gas, means torming a hot working space or variable volume and connected to said cold working space, both or said means including a bellows-like member, means for heating through said bellows-like member, the gas within said cold space and means to vary the volume or the hot working space and cold working space in phase differences.

3. A hot. gas engine comprising means forming a cold working space of variable volume and adapted to receive a working gas, means forming a hot working space or variable volume, a duct connecting said hot working space to said cold working space, both of said means including a bellows-like member, means for heating the working gas within said hot space, means for cooling the gas within said cold space, gear means connected to said bellows to vary the volume of the hot working space and cold working space in phase differences, and a regenerator in said duct.

JACOB WILLEM LAURENS K6HLER. CORNELIUS OTTO JONKERS. WlLLEM HENDRIK STIGTER. AUGUST ALBERT LIEBE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,180,947 Scott Apr. 25, 1916 2,368,101 Btittcher Jan. 30, 1945 2,376,214 Webster May 15, 1945 

